Apple has been long-rumored to be prepping a Spotify and Pandora competitor called iRadio, but there has been one issue solidifying plans for its streaming service – getting all of the big three music labels on board. Fortunately with Apple’s developer conference fast approaching, AllThingsD’s sources say that the final music label, Sony Music, is now in the bag.

After finally getting Sony’s signature and all three major music labels on board – that includes Warner Music Group, Universal Music Group, and Sony Music – Apple may announce iRadio at the conference as early as Monday. Still, it’s very possible that this is a pre-announcement of sorts: Developers will get an early look at Apple’s music streaming service presumably as a way to get potential third-party developers on board, and the rest of us will likely have to wait to get our hands on the service.

Reportedly, the holdup with Sony was the fact that the music label wanted to earn royalties on every single Sony-owned song, even if the track was skipped or not played to its entirety. Whether Sony got its way or Apple talked them down is unclear, but Billboard reports that regardless, it was difficult for Apple to get all the publishers on board. Apple was offering 4.1 percent of ad revenue to the labels, while they were asking for between 10-15 percent. The agreement was eventually settled at 10 percent.

There aren’t too many details on what iRadio will look like, but what’s rumored is that it will work much like Pandora, but offer users the ability to play music stations based on listening habits. It won’t be an on-demand service, however, like Rdio, Spotify, and Rhapsody, so you won’t necessarily be able to pick the songs you want to listen to – hence Apple calling the service “iRadio.” And to generate revenue, Apple has integrated its mobile ad platform, iAds.

According to the report, Apple isn’t entirely out of the clear with Sony. The platform may still be working on finalizing deals with Sony’s music publishing arm, Sony/ATV Music – this arm includes the acquired EMI Music publishing. However Billboard’s sources claim that Sony/ATV have finally signed with Apple’s iRadio.

Come Monday, it looks like we can expect the official announcement with all label details in tow.